We can model the problem in many different ways.
One example is to divide 12 counters (modelled as circles) into six boxes (modelled as square)
We have two circles inside each box
The model is shown in diagram below
<span>0.977
So we have a population with the mean being 0.8750 and the standard deviations being 0.0011. So let's see how many standard deviations we need to be off by to exceed the specifications.
Low end
(0.8725 - 0.8750)/ 0.0011 = -0.0025/0.0011 = -2.272727273
High end
(0.8775 - 0.8750)/ 0.0011 = 0.0025/0.0011 = 2.272727273
So we need to be within 2.272727273 deviations of the mean. Let's use a standard normal table to look up that value, which is 0.48848, which is half the percentage. So 0.48848 * 2 = 0.97696, rounding to 3 digits gives 0.977</span>
When the ball will hit the ground, the height will be zero. So we need to replace
with 0 in our equation, and solve for
:
To solve this equation we are going to use the quadratic formula:
.
From our height equation, we can infer that
,
, and
. So lets replace those values in our quadratic formula to find
or
or
Since time cannot be negative,
is the solution of our equation.
We can conclude that the ball will hit the ground after
2.71 seconds.
I don’t understand how to do this
